National Primary Drinking Water Regulations: Minor Correction to Stage 2 Disinfectants and Disinfection Byproducts Rule and Changes in References to Analytical Methods

In this action, EPA is making a minor correction to the Stage 2 Disinfectants and Disinfection Byproducts Rule (DBPR) and minor, unrelated, editorial changes in references to analytical methods in the regulations. EPA promulgated the Stage 2 Disinfectants and Disinfection Byproducts Rule on January 4, 2006. A requirement for ground water systems serving 500-9,999 people was unintentionally excluded from the final rule. As a result, the rule allowed for less routine compliance monitoring than intended for this category of public water systems (PWSs). These PWSs should have been required to monitor for both total trihalomethanes (TTHM) and haloacetic acids (HAA5) concentrations at two locations. Due to the error, they were only required to monitor for either TTHM or HAA5 at two locations. EPA is also making minor, unrelated changes in the regulations by adding references to the list of analytical methods approved under the Expedited Approval Process, removing references to outdated methods, and specifying a new source for the publication titled Technical Notes on Drinking Water Methods.